Stephen K. Nugent

Effects of closed-chest cardiac massage on intracranial pressure.

: Closed-chest cardiac massage results in a marked increase in intrathoracic pressure and unusual patterns of blood flow. Among the physiological consequences of these changes appears to be a marked increase in intracranial pressure associated with chest compression as documented by the following patient case studies. While temporary, the marked nature of this rise in intracranial pressure suggests that the technique of closed-chest massage may, in itself, be responsible for clinically significant alterations in cerebral hemodynamics.

Pharmacology and use of muscle relaxants in infants and children

Succinylcholine is a short-acting depolarizing neuromuscular blocker used to facilitate intubation; pancuronium is a longer-acting, nondepolarizing agent commonly employed to control ventilation in pediatric patients. The neuromuscular block produced by both drugs may be modified by patient age, acid-base and electrolyte status, body temperature, and drugs such as aminoglycoside antibiotics; adjustment in dose or in technique of administration may be required. Cardiovascular side-effects, primarily arrhythmias, are occasionally associated with the use of either agent. In contrast to that of succinylcholine, the paralysis from pancuronium is pharmacologically reversible with the combination of atropine and neostigmine.

Neurogenic pulmonary edema in childhood

Three patients presenting with pulmonary edema associated with head trauma and increased intracranial pressure are described. Pulmonary edema is a clearly recognized complication of head trauma; the pathogenic mechanisms appear to be regulated by increased intracerebral pressure, sympathetically induced vascular hypertension, and increased pulmonary capillary permeability. If there is evidence that neurogenic pulmonary edema is the underlying etiology, therapeutic modalities should be directed at reducing intracranial pressure and strict attention paid to the interaction between intrathoracic and intracranial pressures in order to avoid the high mortality rate associated with this condition.

Control of cerebral circulation in the neonate and infant

Although much information is known about the factors controlling cerebral blood flow in the adult, there are significant physiological differences between the neonate, infant, and the adult. Therefore, it is not possible directly to transfer information concerning control of cerebral blood flow in the adult to the pediatric age population. A review of age-related differences in critical values of arterial oxygen tension (PaO2), arterial carbon dioxide tension (Paco2), systemic arterial pressure and cerebral perfusion pressure (CPP) confirms that it is necessary to establish critical values in neonates and infants for each of these variables, as well as for any possible sympathetic nervous system influences on cerebral blood flow.

Resuscitation and intensive care monitoring following immersion hypothermia.

Neurologic recovery occurred in a 3-year-old patient following immersion hypothermia and prolonged cardiopulmonary resuscitation. Recognition of hypothermia in the near-drowning victim is imperative for appropriate resuscitative efforts. Intensive care monitoring (intracranial pressure, pulmonary artery catheterization) facilitates patient management and optimum neurologic recovery.

Monitoring cerebral electrical function in the ICU.

The cerebral function monitor (CFM) (Devices Unlimited) is a single-channel, bipolar ECG device modified for continuous recording of cortical electrical activity. We have found the CFM useful in the Pediatric Intensive Care Unit (PICU), particularly in seizure patients, patients with increased intracranial pressure, and after cardiorespiratory arrest. The device and our experience with its use in the PICU are described in this paper.

Experimental evaluation of 2F transthoracic thermodilution cardiac outputs in small animals.

Cardiac output can be measured with a computer using a 2F transthoracic catheter placed during surgery. When injections are made into a central venous catheter, this technique allows for cardiac output measurements to be made in children with complex congenital heart disease not appropriate for placement of a transvenous pulmonary artery catheter. Using rabbits similar in size to the infants most likely to need this technique, 26 experimental comparisons of thermodilution and indocyanine green dye cardiac outputs were made with cardiac outputs as low as 0.2-0.4 liter/min. The relationship between green dye and thermodilution was statistically significant (p less than 0.001) and almost linear (r = 0.92). This documents the validity of both the 2F transthoracic catheter technique in the low range of cardiac outputs appropriate for infants and children.

Electrocardiographic abnormalities in infants and children with neurological injury.

Electrocardiographic (ECG) abnormalities were found in 15 of 20 consecutive children (75%) admitted to the Pediatric ICU (PICU) with central nervous system injury produced by trauma or neurosurgical procedures. The ECG abnormalities included prolonged qTc, U waves, and notched T waves as well as ventricular arrhythmias. The high frequency and potential seriousness of this problem in infants and children suggests that neurogenic ECG changes should be looked for in all infants and children with neurological insults.